• 한국도로학회논문집
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• 제13권4호
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• pp.81-91
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• 2011

본 연구는 연속철근 콘크리트 포장(CRCP: Continuously reinforced concrete pavement)에서 단부 앵커러그 유무에 따른 종방향 변위 비교를 통해 앵커러그의 필요성을 분석하고 내부 수평균열의 수직방향 변위 측정을 통해 이러한 균열이 CRCP의 공용성에 미치는 영향을 분석하기 위하여 수행되었다. 앵커러그 구간 절단 전 거동 측정은 6월 중에 12일간 계측하였으며, 앵커 러그 구간 절단 후의 측정은 절단 시 슬래브에 급격히 발생하는 변위가 사라진 이후 8월 중에 14일 동안 계측하였다. 이와 같은 단기간의 계측 결과 CRCP 단부의 종방향 변위는 앵커러그가 설치되어 있는 경우에는 모든 위치에서 일일 변위 변화가 0.1mm 이내로 종방향 거동이 거의 발생하지 않았다. 단부에 앵커러그가 설치되지 않은 경우에는 변위가 자유 단부 부근에서만 주로 발생하며 종방향 변위 변화가 작아서 팽창줄눈으로 처리하여도 적절할 것으로 예측되었으나, 향후 추가연구에 의해 사계절 온도변화에 따른 단부의 거동을 확인할 필요가 있을 것으로 판단된다. 내부 수평균열은 거동 측정 결과 거의 비활성균열이며 전체적인 슬래브의 수직변위에 영향을 미치지 않았다. 따라서 수평균열이 슬래브를 상하로 분리시켜 CRCP의 구조적인 성능 및 공용성의 저하를 유발하지는 않을 것으로 분석되었다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.193-198
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• 2002

In 1his paper, applicability of laser welding to joining process of single crystal nickel base superalloy turbine blades was investigated. Because heat input of laser welding is more precisely controlled 1han TIG welding, it is possible to optimize solidification microstructure of the welds. Since in single crystal nickel base superalloy the crystal orientation have a significant effect on the strength, it is important to control the solidification microstructure in the fusion zone. A single crystal nickel base supera1loy, CMSX-4, plates were bead-on welded and butt welded using a $CO_2$ laser. The effects of microstructure and crystal orientation on properties of the weld joints were investigated. In bead-on weldling, welding directions were deviated from the base metal [100] direction by 0, 5, 15 and 30 degrees. The welds with deviation angles of 15 and 30 degrees showed fusion zone transverse cracks. As the deviation angles became larger, the fusion zone had more cracking. In the cross section microstructure, the fusion zone grains in 0 and 5 degrees welds grew epitaxially from the base metal spins except for the bead neck regions. The grains in the bead neck regions contained stray crystals. As deviation angles increased, number of the stray crystals increased. In butt welding, the declinations of the crystal orientation of the two base metals varied 0, 5 and 10 degrees. All beads had no cracks. In the 5 degrees bead, the cross section and surface microstructures showed that the fusion zone grains grew epitaxially from the base metal grains. However, the 10 degrees bead, the bead cross section and surface contained the stray crystals in the center of the welds. Orientations of the stray crystals accorded with the heat flow directions in the weld pool. When the welding direction was deviated from the base metal [100] direction, cracks appeared in the area including the stray crystals. The cracks developed along the grain boundaries of the stray crystals with high angles in the final solidification regions at the center of the welds. The fracture surfaces were covered with liquid film. The cracks, therefore, found to be solidification cracks due to the presence of low melting eutectic. As the results, in both bead-on welding and butt welding the deviation angles should be control within 5 degrees for preventing the fusion zone cracks. To investigate the mechanical properties of the weld joints, high temperature tensile tests for bead-on welds with deviation angles of 0 and 5 degrees and the butt welds with dec1ination angles of 0, 5 and 10 degrees were conducted at 1123K. The the tensile strength of all weld joints were more 1han 800MPa that is almost 80% of the tensile strength of the base metal. The strength of the laser weld joints were more than twice that of tue TIG weld joints with a filler metal of Inconel 625. The results reveals 1hat laser welding is more effective joining process for single crystal nickelbase superalloy turbine blades 1han TIG welding.

• 한국결정성장학회지
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• 제21권4호
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• pp.158-163
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• 2011

박막 태양전지의 저가 고효율화를 실현하기 위해 넓은 면적의 기판 위에 코팅이 가능하며 진공의 유자가 필요 없기 때문에 장치가 간단하고 고순도의 균질한 박막을 얻을 수 있고 박막의 조성을 쉽게 조절할 수 있는 Sol-Gel법을 이용 하였다. Se보다 저가이며 독성이 없고 풍부한 원료인 S로 치환하여 사용하며 Cu/In비 값을 조절하고 tetragonal chalcopyrite $CuInS_2$의 열처리 온도에 따른 박막의 구조적, 광학적 특성에 미치는 변수들의 영향을 알아보았다. XRD pattern을 관찰한 결과 Cu/In비가 1.0일 때 $2{\theta}=27.9^{\circ}$에서 주피크가 가장 강하게 나타났으며 (112) 방향의 배향성을 가진 chalcopyrite상임을 확언 할 수 있었다. 열처리 온도가 증가할수록 (112) 면의 강도가 커지며 $500^{\circ}C$에서 열처리를 한 $CuInS_2$ 박막은 tetragonal 구조의 화학량론적 $CuInS_2$ 특징을 나타내고 본 실험의 샘플의 격자상수를 측정한 값이 a = 5.5032, c = 11.1064 ${\AA}$이며 JCPDS(Joint Committee on Powder Diffraction Standards)에 보고된 데이터 a = 5.523, c = 11.14 ${\AA}$과 거의 일치하였다. 광학적 특성을 알아보기 위해 측정한 광투과율은 가시광선 영역(380~770 nm)에서 전체적으로 30% 이하로 나타났다.

• Journal of Acupuncture Research
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• 제23권1호
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• pp.187-215
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• 2006

Objectives : To determine whether the pragmatic acupuncture treatment provides more effective pain relief than treatment using the same acupuncture point to the all patients. Methods : We randomly allocated participants to treatment group 1 and 2. The group 1 is the pragmatic treatment group and the group 2 is using the same acupuncture point to the all patients. Primary outcomes were measured by the Western Ontario and McMaster Universities Osteoarthritis index(WOMAC) pain and function scores at 4, 8, and 14 weeks. Secondary outcomes were measured by 100mm VAS(Visual Analog Scale), ROM(Range of Motion) using Goniometer, and pain threshold using pressure algometer. Results : When patients were extension of the knee, they were statistically significant in improvement of the ROM in 14 weeks. Whole body condition and pain rate through VAS measurement were improved significantly in 14 weeks. Also pain score and function score of WOMAC were improved significantly in 14 weeks. We could get difference in pain score of two acupuncture groups significantly in 14 weeks. But we could not get difference in whole score of two acupuncture groups significantly. Local temperature using T.C thermometer was changed significantly in 14 weeks. But we could not get difference in whole score of two acupuncture groups significantly. Excluding above item, DITI, pain threshold, and ROM of the knee flexion were no difference in before and after treatment.

• 안보군사학연구
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• 통권7호
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• pp.271-303
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• 2009

"Ubiquitous sensor network" definition is this-Someone attaches electro-magnetic tag everything which needs communication between man to man, man to material and material to material(Ubiquitous). By using attached every electro-magnetic tag, someone detects it's native information as well as environmental information such as temperature, humidity, pollution and infiltration information(Sensor). someone connects it realtime network and manage generated information(Network). 21st century's war is joint combined operation connecting with ground, sea and air smoothly in digitalized war field, and is systematic war provided realtime information from sensor to shooter. So, it needs dramatic development on watch reconnaissance, command and control, pinpoint strike etc. Ubiquitous computing and network technologies are essential in national defense to operate 21st century style war. It is possible to use many parts such as USN combined smart dust and sensor network to protect friend unit as well as to watch enemy's deep area by unmanned reconnaissance, wearable computer upgrading soldier's operational ability and combat power dramatically, RFID which can be used material management as well as on time support. Especially, unmanned watch system using USN is core part to transit network centric military service and to get national defense efficiency which overcome the dilemma of national defense person resource reducing, and upgrade guard quality level, and improve combat power by normalizing guardian's bio rhythm. According to the test result of sensor network unmanned watch system, it needs more effort and time to stabilize because of low USN technology maturity and using maturity. In the future, USN unmanned watch system project must be decided the application scope such as application area and starting point by evaluating technology maturity and using maturity. And when you decide application scope, you must consider not only short period goal as cost reduction, soldier decrease and guard power upgrade but also long period goal as advanced defense ability strength. You must build basic infra in advance such as light cable network, frequency allocation and power facility etc. First of all, it must get budget guarantee and driving force for USN unmanned watch system project related to defense policy. You must forwarded the USN project assuming posses of operation skill as procedure, system, standard, training in advance. Operational skill posses is come from step by step application strategy such as test phase, introduction phase, spread phase, stabilization phase and also repeated test application taking example project.

• 한국도로학회논문집
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• 제19권3호
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• pp.31-43
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• 2017

PURPOSES : The objective of this study is to verify the effect of fiber grid reinforcement on the long-term performance of asphalt pavement overlaid on old concrete pavement by performing field investigation, laboratory test, and finite element analysis. METHODS : The reflection cracking, roughness, and rutting of fiber grid reinforced overlay sections and ordinary overlay sections were compared. Cores were obtained from both the fiber grid reinforced and ordinary sections to measure bonding shear strength between the asphalt intermediate and asphalt overlay layers. Fracture energy, displacement after yield, shear stiffnesses of the cores were also obtained by analyzing the test results. Finite element analysis was performed using the test results to validate the effect of the fiber grid reinforcement on long-term performance of asphalt pavement overlaid on the old concrete pavement. The fatigue cracking and reflection-cracking were predicted for three cases: 1) fiber grid was not used; 2) glass fiber grid was used; 3) carbon fiber grid was used. RESULTS : The reflection-cracking ratio of fiber grid reinforced sections was much smaller than that of ordinary sections. The fiber grid reinforcement also showed reduction effect on rutting while that on roughness was not clear. The reflection-cracking was not affected by traffic volume but by slab deformation and joint movement caused by temperature variation. The bonding shear strength of the fiber grid reinforced sections was larger than that of the ordinary sections. The fracture energy, displacement after yield, and shear stiffnesses of the cores of the fiber grid reinforced sections were also larger than those of the ordinary sections. Finite element analysis results showed that fatigue cracking of glass or carbon fiber grid reinforced pavement was much smaller than that of ordinary pavement. Carbon fiber grid reinforcement showed larger effect in elongating the fatigue life of the ordinary overlay pavement compared to glass fiber grid reinforcement. The binder type of the overlay layer also affected the fatigue life. The fiber grid reinforcement resisted reflection-cracking and the carbon fiber grid showed the greater effect. CONCLUSIONS :The results of field investigation, laboratory test, and finite element analysis showed that the fiber grid reinforcement had a better effect on improving long-term performance of asphalt pavement overlaid on the old concrete pavement.

• 마이크로전자및패키징학회지
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• 제17권3호
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• pp.17-26
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• 2010

반도체 패키지에 사용되고 있는 유연 솔더는 환경 보호 필요성 대문에 무연 솔더로 빠르게 대체되고 있다. 이와 같은 무연 솔더에 대한 여구는 주로 재료의 발견과 공정 적응성의 관점에서 이루어졌을 뿐, 기계적인 성질이나 신뢰성의 관점에서의 연구는 많이 이루어지지 않았다. 본 논문에서는 무아레 간섭계를 이용하여 유연 솔더와 무연 솔더 실장 WB-PBGA 패키지 결합체의 온도변화에 대한 열-기게적 거동을 해석하였다. 실시간 무아레 간섭계를 이용하여 각 온도 단계에서 변위 분포를 나타내는 간섭무늬를 얻고, 그로부터 유연과 무연의 솔더 조인트를 갖는 WB-PBGA 패키지의 굽힘 변형 거동 및 솔더 볼의 변형률을 비교 분석하였다. 분석결과를 보면 유연 솔더 실장 패키지 결합체의 솔더 볼은 칩경계 부근인 #3 솔더 볼에서 발생하는 전단변형률이 파손에 큰 영향을 미치며, 무연 솔더가 실장된 패키지 결합체의 솔더 볼은 가장 바깥 부근인 #7 솔더 볼에서 발행하는 수직 변형률이 파손에 큰 영향을 미칠 것으로 예측된다, 또한 무연 솔더 실장 패키지 결합체는 같은 온도 조건에서 유연 솔더 실장된 패키지에 비해 굽힘 변형이 휠씬 크게 발생될 뿐 아니라 솔더 볼의 유효변형률도 10% 정도 크게 발생하는 것으로 나타나서 열변형에 의한 파손에 취약할 것으로 예측된다.

• 한국도로학회논문집
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• 제10권4호
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• pp.9-18
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• 2008

줄눈 콘크리트포장(JCP-Jointed Concrete Pavement)의 경우 포장단면 온 습도차에 의해 슬래브 내의 컬링이 발생하게 된다. 컬링에 의해서 발생하는 슬래브의 휨 형상 및 크기는 포장내 응력 및 평탄성에 영향을 미치기 때문에 포장의 구조적, 기능적 성능에 중요한 영향을 줄 수 있다. 슬래브의 휨 형상을 직접 측정하는 것은 시공초기에 포장내에 다량의 계측기를 매설하여야 하며, 시공초기부터 거동의 정교한 측정이 필요하고 고가의 실험비용 및 기술적 인 어려움을 갖고 있다. 본 연구에서는 현장에서 손쉽게 획득할 수 있는 프로파일 데이터(Profile Data)에 파워 스펙트럼 분석(Power Spectrum Density Analysis) 및 역 푸리에 변환(Inverse Fast Fourier Transform) 기법 등을 적용하여 임의의 시간에서 줄눈 콘크리트포장의 슬래브 휨 형상을 측정하는 방법을 개발하였다. 개발한 기법의 실효성을 검증하기 위하여 국내 중부내륙에 위치한 시험도로 줄눈 콘크리트 포장에서 시간대별 프로파일을 측정하고 이 데이터로부터 슬래브 휨 형상을 도출하여 그 결과를 검토하였다. 또한 동 시간대의 연속철근 콘크리트포장(CRCP- Continuous Reinforced concrete Pavement) 구간에서의 프로파일 데이터를 분석하고 이를 줄눈 콘크리트포장에서의 결과와 비교하여 개발한 슬래브 휨 형상 추출기법의 타당성을 검증하였다.

• Archives of Pharmacal Research
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• 제26권2호
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• pp.168-172
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• 2003

Radiation synovectomy is one of the most useful methods for treating patients with refractory synovitis because of its convenience, long-term effects, repeatability and the avoidance of surgery. In this study, we investigated the toxicity, stability and biodistribution of a rhenium-188 ($^{188}$Re)-tin colloid to evaluate its suitability as a synovectomy agent. Twenty four hours after injecting the $^{188}$Re-tin colloids (74 KBq/0.1 mL) into the tail vein of ICR mice, most of the $^{188}$Retin colloidal particles was found in the lungs. In addition, there were no particle size changes at either room temperature or at $37^{\circ}C$ after injecting the $^{188}$Re-tin colloids in human plasma and synovial fluid. In vitro stability tests showed that the $^{188}$Re-tin colloid remained in a colloidal form without a critical size variation over a 2-day period. We investigated the leakage of $^{188}$Retin colloids from the intraarticular injection site with gamma counting in New Zealand white rabbits. The $^{188}$Re-tin colloids (55.5 MBq/0.15 mL) were injected at the cavum articular and the mean retention percentage of the $^{188}$Re-tin colloid was 98.7% for 1 day at the injection site, which suggests that there was neither change in the particle size nor leakage at the injection sites. In the biodistribution study with the SD rats, the liver showed the highest radioactivity (0.0427% ID/organ) except for the injected knees (99.49%). In the SD rats, mild toxicities including the skin or a synovium inflammation were observed as a result of a radioactivity of 15 mCi/kg at the intraarticular injection site. However, there was no systemic toxicity. In the Ovalbumin (OVA)-induced arthritic rabbits, the $^{188}$Re-tin colloid improved the macroscopic, the histological score and reduced the knee joint diameter when compared to the arthritic control. In conclusion, a $^{188}$Re-tin-colloid is considered as a strong candidate for radiation synovectomy with a superior efficacy and safety.

• 마이크로전자및패키징학회지
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• 제14권1호
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• pp.33-38
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• 2007

본 실험에서는 Non-Conductive Adhesive (NCA) 와 고분자 범프를 이용한 COG (Chip-on-glass) 접합에 대하여 연구하였다. 산화막이 증착된 Si 기판 위에 고분자 범프를 사진식각 방법으로 형성하고, 고분자 범프 위에 직류 마그네트론 스퍼터링 방법으로 금속 박막층을 증착하였다. 기판으로는 Al을 증착한 유리기판을 사용하였다. 두 종류의 NCA를 사용하여 $80^{\circ}C$에서 하중을 변화시켜가며 접합을 실시하였다. 접합부의 특성을 평가하기 위하여 4단자 저항 측정법을 이용하여 접합부의 접속 저항을 측정하였으며, 주사전자현미경을 이용하여 접합부를 관찰하였다. 신뢰성은 $0^{\circ}C$ 와 $55^{\circ}C$ 사이에서 열충격 실험을 2000회까지 실시하여 평가하였다. 신뢰성 측정 전 접합부의 저항 값은 $70-90m{\Omega}$을 나타내었다. 200MPa 이상의 접합 압력에서는 고분자 범프가 NCA 의 필러 파티클에 의해 손상된 것을 관찰하였다. 신뢰성 측정 후 일부 범프가 fail 되었는데 범프의 fail 원인은 범프의 윗부분보다 상대적으로 금속층이 얇게 증착된 범프의 모서리 부분의 금속층의 끊어졌기 때문이었다.